Process of producing capsule-coated sheets

ABSTRACT

Microcapsule coated sheets can be efficiently produced by a process wherein excess microcapsule coating composition is removed from a running base sheet by a mechanical tool which by shear force meters and levels the microcapsule coating composition, if the microcapsule coating composition has a solids content of about 20 to 80 weight percent and a viscosity of 50 to 50,000 c.p.

United States Patent Kanda et al.

PROCESS OF PRODUCING CAPSULE-COATED SHEETS Inventors-. Masao Kanda;Keiso Saeiki, both of Fujinomiya, Japan Assignee: Fuji Photo Film (10.,Ltd., Minami- Ashigara, Japan Filed: Jan. 2, 1974 Appl. No.: 430,015

Related US. Application Data Continuation of Scr. No. 203,302, Nov. 30,1971, abandoned.

Foreign Application Priority Data Field of Search... 117/36.2, 64 R,65.2, 111 H, 117/154; 252/316 References Cited UNITED STATES PATENTS8/1947 Dickcrman et al. 1 17/11 1 [111 3,897,578 [451 July 29,1975

3,138,515 6/1964 Dritz 117/36.2 X

3,309,224 3/1967 Weber 117/65.2 X

3,386,822 6/1968 Brynko 117/65.2 X 3,418,250 12/1968 Vassiliades....424/17 X 3,418,656 12/1968 Vassi1iades.... 424/17 X 3,468,700 9/1969Long 117/111 3,632,296 l/l972 Pandell et a1. 117/141 3,647,525 3/1972Dahlgren 117/111 3,660,304 5/1972 Matsukawa 1l7/62.2 X

Primary Examiner-Michael R. Lusignan Attorney, Agent, or Firm--Sughrue,Rothwell, Mion, Zinn & Macpeak [57] ABSTRACT Microcapsule coated sheetscan be efficiently produced by a process wherein excess microcapsulecoating composition is removed from a running base sheet by a mechanicaltool which by shear force meters and levels the microcapsule coatingcomposition, if the microcapsule coating composition has a solidscontent of about 20 to 80 weight percent and a viscosity of 50 to 50,000c.p.

3 Claims, 8 Drawing Figures PATENTEU JUL29 75 FIG. 60

FIG. 6b

PROCESS OF PRODUCING CAPSULE-COATED SHEETS This is a continuation ofapplication Ser. No. 203,302, filed Nov. 30, 1971, now abandoned.

BACKGROUND OF THE INVENTION 1. Field of the Invention The presentinvention relates to a process for producing capsule-coated sheets, andmore particularly it relates to a process and apparatus for applying acoating composition consisting of minute capsules onto moving support.

2. Description of the Prior Art The minute capsules constitutingcapsule-coated sheets are easily broken by pressure, so that an airdoctor coater in which pressure is not directly applied to such capsulehas been used as the coating means for coating microcapsulescompositions onto moving supports e.g., see U.S: Patent SpecificationNos. 3,l 86,861; 3,472,674 and British Patent Specification No.1,176,469.

However, with such conventional coating apparatus, low-solids content,low-viscosity coating compositions must be used so that when metering byblowing off excess coating composition with air jet blow the air doctorcoater, the coating composition is blown off in the form of fineparticles. These particles contaminate the tip end of the air doctorblade and lead to coating stripes being produced on the coated surface.In order to prevent this, frequent cleaning is necessary which requiresinterrupting the coating operation so that the rate of productiondecreases considerably.

As will be further described later, although it is desirable to increasethe solids content of the coating composition, the viscosity of thecoating composition in-- creases by increasing the solids content of thecoating composition, so that in order to meter a predetermined quanityof coating, it is necessary to increase the wind pressure of the air jetwhich increases the spattering of the excess coating compositioncontaminating the doctor blade whereby more frequent cleaning becomesnecessary. This prevents increasing the solids content of the coatingcomposition, and a low-solids content coating composition has to beused. Accordingly, a large drying device is required to remove a largequantity of water, which in turn requires a large space and excessiveequipment cost and operating cost. Furthermore, since the drying deviceis large, the path of the support is long during running and a greatamount of support material is lost due to breakage thereof, with adecrease in production rate.

SUMMARY OF THE INVENTION The present invention overcomes theabovementioned disadvantages, and is characterized in that it uses acoating apparatus comprising a coating tool for applying a surplusamount of coating composition onto a support and a doctor blade ormetering bar acting to measure the coating composition and to equalizeit to thus apply a coating composition consisting of minute capsulesonto a running support.

One object of the present invention is to provide a method and apparatusfor applying a high-density, high-viscosity capsule coating compositiononto a support.

Another object of the present invention is to provide a coatingapparatus for a capsule coating composition which does not spatter thecoating composition by the spraying of an air jet, whereby a continuouscoating operation can be effected.

Still another object of the present invention is to provide a coatingapparatus for a capsule coating composition which uses a small dryingdevice, and thus the space required for installation of the machinebecomes small, and therefore the costs of equipment and operation can beremarkably reduced.

Other objectsof the present invention will be made clear from thefollowing description as well as from the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 through 4 show embodiments ofapparatus appropriate for carrying out the process of the presentinvention.

FIGS. 5A, 5B, 6A and 6B are microscopic photographs showingmicro-capsule coating surfaces produced in accordance with the presentinvention taken by scanning electron microscope FIGS. 5B and 6B are of ahigher magnification than FIGS. 5A and 6A.

DETAILED DESCRIPTION OF THE INVENTION According to the present inventionit has been found that the above and the other objects are attined byusing a coating apparatus provided with a coating tool for applying anexcess of coating composition on a support when the coating composition,which comprises fine particles, is applied onto a running support, thecoating tool being used in combination with a doctor blade or a meteringbar.

In general, the coating apparatus known as blade coaters or metering barcoaters involve the operation of scraping off the excess coatingcomposition on the support by pressing a mechanical tool directly on thecoating composition applied on the running support. These devices can beadapted to use highconcentration, high-viscosity coating composition,but the blade coater and the metering bar coater give an excessiveshearing stress on the coating composition at the process of meteringexcessive amounts of coating composition. Such apparatus is thus notused as coating apparatus for coating compositions consisting of finecapsules which are readily broden by pressure, thus air knife coaters,which have the many drawbacks mentioned above, are extensively used.

The inventors have found that it is possible to apply a predeterminedquantity of coating composition without breaking the minute particlesonto a running support despite the high shearing force exerted by bladecoaters and metering bar coaters.

In using a coating composition comprising rupturable particles in thepresentinvention, to obtain a most favorable coating adaptability it isnecessary that the solids content in the capsule coating composition befrom about 20 to about and the viscosity be in the range of 50 to 50,000c.p. Examples of processes of producing such fine capsular compositionwill be enumerated below, but the present invention should not belimited thereto (all viscosities measured at 25C). It shall beunderstood that there is no special criticality to the exactmicrocapsule size selected, but those skilled in the art willappreciated such are preferably of a size, usally expressed as diameter,less than about ;1., preferably about 10 p. to about 50 11..

1. Phase separation method from aqueous solution (U.S. PatentSpecification Nos. 2,800,457 and 2,800,458 with the one most generallyused utilizing coacervation of hydrophilic colloid sols.

2. lnterfacial polymerization (Japanese Patent Publication Nos.l9,574/l963, 446/1967, 771/1967, British Patent Specification Nos.867,797; 950,443; 989,264; 1,09l,076).

The capsule wall film is initially formed in the presence of a monomerof initial condensate (which is the first wall film forming substance)in an oily liquid which is to be contained therein. The completedpolymer to form the wall film substance of the micro-capsules is notpresent in the first stage. Then a second wall film forming substancewhich can react with said first wall film forming substance is dissolvedin a polar solvent which does not mix with the oily liquid, whereafterpolymerizing the first wall film forming substance and the second wallfilm forming substance at the interface of the oil drops of the oilyliquid and the polar solvent is conducted to form a wall film.

3. Method comprising the polymerization of monomer in oil drops.(Japanese Patent Publication No. 9168/1961).

After dissolving compounds having double bonds such as acryl compounds,styrene, vinyl acetate, in oil drops, a radical polymerization isconducted using peroxides as the catalyst to produce oil-insolublepolymers.

4. Fusion-dispersion cooling process (British Patent Specification Nos.952,807 and 965,074).

A stablilizing substance which is a solid at normal temperature, and aliquid under heat, is utilized as the capsule wall film. A wax orthermoplastic resin is usually used.

5. Spray drying process (U.S. Patent Specification No. 3,] 1 1,407,British Patent Specification No. 930,422).

Solid particles or liquids are emulsified and dispersed in a polymersolution which is introduced in a spray dryer. At the instant thedispersed liquid is driven out in the form of minute particle from theatomizer the substances contained therein are surrounded by the polymer.

6. Internal accumulation process (Japanese Patent Application Nos.38087/1968, 69448/1969).

In these processes, the same or different kinds of compounds whichproduce, by mutual reaction, oilinsoluble, high-molecular substances aredissolved in an oily liquid in the presence of a low-boiling solvent ora polar liquid forming a continuous phase and a polar solvent compatibletherewith, and after dispersing and emulsifying the product in the polarliquid forming the continuous phase, the system is heated to transferthe wall film forming substance onto the surface of the oil particles,whereafter the high molecular weight material forming reaction at thesurface of the oil granules proceeds to form the wall film.

The microcapsule coating liquid obtained by the abovedescribed processesis regulated so as to have a solids content of from about to about 80and a viscosity of 50 to 50,000 c.p. by concentration, centrifugalseparation, spray drying, dilution, a combination of such processes, andif necessary, by adding a viscosity intensifier.

In this case, it is also possible to increase the coating adaptabilityof the capsule coating composition by adding water-soluble'binder,synthetic resin emulsion etc.

The present invention is characterized by applying a coating compositionof microcapsules prepared as described above on a running support bymeans of a coating apparatus comprising a coating tool for applying asurplus of coating composition on the support and a doctor blade ormetering bar for metering and equalizing the coating composition.

The coating apparatus the present invention will now be described withreference to the accompanying drawings.

FIG. 1 is a schematic view showing a pond-type blade coater which is arepresentative blade coater. The pond-type blade coater comprises arubber-coated backing roll 5 holding support sheet to be coated, acoater consisting of a flexible blade 1 and a supporting frame 2 whichholds coating composition by forming a reservoir between blade '1 andbacking role 5 (or the running support 6 when present), and a conduit 4for supplying coating composition comprising the microcapsules in liquidreservoir 3 formed the coater and the running support held by thebacking role 5. Conduit 4 can also serve as an overflowing to keep theliquid level of the liquid reservoir 3 constant. The mechanism is soarranged that the running support sheet 6 which is coated by liquidpressure produced at the coating composition reservoir 3, and apredetermined coating amount is obtained'by the shearing force producedby pressing the blade 1 which forms the coter onto the support sheet 6.

Another type of blade coater is shown in FIG. 2, and this is one type offountain blade coater.

Referring now to FIG. 2, a coating composition consisting ofmicrocapsule is supplied to a coating tool 12 at the position to becoated by applying pressure by a pump, whereby a surplus of coatingcomposition which is formed of uniform, minute microcapsules is extrudedthrough slit 13 of coating tool 12 under pressure, whereafter thecoating liquid is applied onto running support sheet 6 held byrubber-coated backing roll 11. The coating liquid over-flown from thecoating tool 12 enters into a coating-composition pan l4, and isrecovered, The coating composition applied on running sheet 6 by thecoating tool 12 is metered by pressing a flexible blade 17 heldby-supporter 16 (placed next to the coating tool 12) against a runningsupport sheet 15 to be coated held by a backing roll 11, thus auniformly coated surface is obtained.

In addition to the pond-type blade coater and the fountain blade coater,there are a number of blade coaters of another types such as theFlexiblade coater, the Flooded nip blade coater and the blade coater inthe coating apparatus of the present invention is intended to includesuch devices as they are all characterized by the common operation ofapplying a surplus of coating composition'comprising microcapsules ontoa running support sheet and pressing a blade fixed transversely to thesupport sheet against the coated surface of the support sheet which hasbeen coated with coating composition, whereby the coating composition ismetered and rendered of uniform thickness.

Although the coating quantity can be regulated by adjusting the shearingforce applied onto the coating composition on the support sheet, theshearing force applied on the microcapsule constituting the coatingcomposition must be of such a degree of force that it will not break themicrocapsules. The shearing force to be applied to the coatingcomposition can be varied according to the running speed of the supportsheet, the thickness and the quality of the blade material, the lengthof the blade, the holding angle of the blade and the hardness of thebacking roll, and furthermore, by varying the solids content and theviscosity of the microcapsule coating composition. The conditions whichwill not break the microcapsules can be determined easily in a mannerknown to the art. In this regard, the size of the microcapulse is notrestricted, but is preferably below 100 microns.

Another coating apparatus in accordance with the present invention willnow be described which relates to a metering bar coater in which a roundbar fixed to extend transverse to the direction of the running sheet isapplied onto the coating surface of the running support sheet coatedwith a coating composition of microcapsules. Such an apparatus alsooperates to provide metering and equalization of the coating surface asin the case of doctor blades.

FIG. 3 one type of metering bar coater, wherein a microcapsule coatingcomposition is introduced into a liquid reservoir 21, a metering bar 24having a small diameter and supported by a suppporter 25 located next toan applicator roll 22 is applied to the coated surface of the supportsheet, the metering bar 24 rotating in a direction reverse to that ofthe running direction of the support sheet 23, whereby surplus coatingcomposition is scraped off and the coated surface is metered andequalized. The capsule coating composition scraped off by the meteringbar 24 enters a liquid reservoir 21 and is recovered from deliveryoutlet 26. A roll 27 arranged in fron of the applicator roll 22 is abacking roll which serves to bring the support sheet into contact withthe applicator roll 22.

The roll 28 positioned at the back of the metering bar 24 serves todetermine the contact angle between the support sheet and the meteringbar 24. Metering bar 24 can be a round bar having a diameter less than50 mm coated with smooth, hard chromium surface, particularly a barhaving a diameter between 3 and 15. Further, the metering bar ispreferably wound with wire, and it is possible to change the quantity ofcoating by selecting the size of the wire.

FIG. 4 shows another type of metering bar coater, in which a coatingcomposition of microcapsules is introduced into the liquid reservoir 32through coating liquid feeding inlet 31 and removed via outlet 33, Thecoating composition is picked up by applicator roll 34 immersed in thecoating composition, and by lowering a backing roll 35, the runningsupport sheet 36 is made to contact on the applicator roll 34,transferring a surplus amount of microcapsule coating composition ontothe sheet, The surplus coating composition is metered by a metering bar38 arranged to contact the microcapsule coated surface of the supportsheet while it is supported by a back up roll 37 positioned next to theapplicator roll 34. Metering bar 38 is preferably a round bar having adiameter less than 50 mm coated with smooth, hard chromium layer,especially a round bar having a diameter of 3 mm. Further, the meteringbar is preferably wound with wire to permit an even more uniform coatingand it is possible to vary the amount of coating by selecting the sizeof wire wound. The metering bar 38 may be fixed, but it is especiallyeffective for metering and equalizing when it is rotated in thedirection oppositve to the running direction of the support sheet 36.The metering bar 38 is supported by a flexible blade holder 39 fixedtransversely to the support sheet, the blade 39 being fixed by a holdingframe 40. By moving supporting frame 40-it is possible to change thepressure of the metering bar 38 on the coating liquid on the sheetsupported by backing roll 37. The coating composition 41 of capsulesscraped off by metering bar 38 is collected in a liquid accumulator 42,and recovered via outlet 43.

As is clear from the above explanation, the metering bar coater is onetype of coating apparatus used in the present invention wherein asurplus of microcapsule coating composition is coated on a runningsupport sheet and, by pressing a metering bar there against which isprovided at a position extending transversely of the support sheet,excess coating composition is metered therefrom and the coated surfaceis made uniform. The shearing force applied on the microcapsules can bevaried by changing the diameter of the metering bar, the rotating speed,the construction of the blade holder, the pressure of the metering baron the support sheet, the size of wire wound around the metering bar,and further, by altering the solids content of the coating composition.

As stated with respect to one type of coating apparatus used in thepresent invention, it is so arranged that a coating tool is directlybrought into contact with the coated microcapsule composition on therunning support sheet, and by scraping off excess microcapsule coatingcomposition metering and equalizing of the coated composition areeffected. It is evident that an extremely large shearing force isappliedonto the microcapsule particles when compared with the meteringaction effected by a conventional air-knife coater used for producingcapsule coated sheets.

Accordingly, although the prior art would lead one to conclude that themicrocapsules might be broken, the inventors have found that thecapsules are not broken by applying a tool directly onto the coatingliquid and by scraping off excess coating composition.

In the case where a thinner coating layer of capsules is to be producedby applying an especially large shearing force using such coating tools,by using a coating composition of microcapsules with a synthetic highmolecule weight polymer as the wall film as shown in following Examples2, 3 and 6 metering is effected by applying the coating tool directlyonto a running support sheet on which the microcapsule coating isapplied, as described previously. It is thus possible to obtain highcoating adaptability, and furthermore a uniformly coated surface can beobtained.- This is because microcapsules with synthetic high molecularweight polymer wall films, e.g., polyurea polyurethanes, are capable offorming microcapsules having a more uniform shape as compared tocapsules having a natural product as the wall film. The physicalstrength of such synthetic capsule wall films is of course, very high.

In some cases, in order to increase the anti-wear property of thecapsule, the support sheet is coated with a microcapsule coatingcomposition having incroporated therein cellulose flocks or the like,but when a blade coater is used which applies a coating compositionconsisting of microcapsules and meters by a shearing force generated bypressing the blade against the coated support sheet supported by abacking roll, cellulose flocks having a large particle size adhere tothe blade and may produce scratches on the coating support sheet.However, it was found that by adapting a metering bar coater whichmeters a microcapsule coating composition to rotate the bar (as shown inFIGS. 3 and 4) in the direction reverse to the running direction of thesupport sheet it was possible to scrape off material such as celluloseflocks so that the possibility scratches was much reduced.

It will be understood that in the present application the term excess"implies an amount of microcapsule composition greater than that desiredin the final product.

Accordingly, the object of the present invention can easily be attainedby applying a coating composition consisting of microcapsules having asynthesized high molecular weight polymer wall film onto support sheetusing a coating device employing a metering bar coater, and thus it ispossible to obtain a capsule-coated sheet having very thin films.

EXAMPLE 1 1.0 part of crystal violet lactone is dissolved into 50 partsof diphenyl chloride, and the product added to an aqueous solutionconsisting of 60 parts of 40C water and gum arabic so as to form anoil-in-water emulsion of 6 10 micron size oil drops. An aqueous solutionformed by dissolving 10 parts of acid-treated gelatin having anisoelectric point of 7.8 in 80 parts of water having a temperature of40C was added thereto followed by 50% acetic acid under constantagitation so as to provide a pH of 4.2. 250 parts of 40C water were thenadded to cause coacervation. A thick liquid film consisting of gelatinand gum arabic formed around the oil particles which had dissolved colorformer thereon. The thick liquid films were then cooled for gellationdown to 10C, and 4 parts of 37% formaldehyde solution added to hardenthe wall films. At this stage, 40 parts of a 10% aqueous solution of thesodium salt of carboxymethyl cellulose was added, followed by dropwiseadding a 10% aqueous solution of sodium hydroxide to increase thehardening of the films with increas ing the pH up tp 9.5 and the watertemperature to 50C.

Centrifuging and concentrating the capsule liquid thus obtained resultedin a solids content of 42%. The capsule liquid thus prepared had aviscosity of 1,500 CF.

The capsule liquid thus obtained was applied onto a base sheet using thefountain blade coater shown in FIG. 2. The coating was effected at arate of 100 m/min as follows: The backing roll was a rubber coated rollhaving a diameter of 960 mm with a hardness of 60 Shore, the blade was0.25 mm thick and made of steel, the 20 mm long blade being flexible andnot fixed to the support frame, the blade angle to the backing roll was50, and the blade pressure was 10 kg/cm The blade scraped the excessfrom the support. After drying, a pressure-sensitive color-forming copysheet was obtained.

When the pressure-sensitive colorforming copy sheet thus obtained wassuperposed on a commercial pressure-sensitive copying clay paper, ablue, clear colored image was obtained on the clay paper by copyingthereon.

After said color forming sheet was heated at 100C for 10 hrs. in an airdrying box, it was superposed on a clay paper, and when it is used fortypewriting, no decrease in-concentration of the colored image was foundas compared to prior to the thermal test. Thus, the capsules haveexcellent heat resistance.

Photographs of the capsule coated surface taken by a scanning electronmicroscope as shown in FIG. 5, and it was found that the capsules werenot broken entirely.

EXAMPLE 2 4 parts of 3-diethylamino-7-dibenzylaminofluorane wasdissolved in 40 parts of diisopropyl-biphenyl and 10 parts ofchlorinated normal paraffine with 14 carbon atoms. To this product therewas added and mixed a solution of 10 parts of toluylenediisocyanate, 6parts of bisphenol A, 0.5 parts of lead octylate and 20 parts ofmethylene chloride to obtain a primary solution.

10 parts of gum arabic was dissolved in 40 parts of water at 30C. Theprimary solution was added thereto and the system emulsified with ahomogenizer, the resulting oil-in-water emulsion having an oil-dropdiameter of 10 15 microns.

The above emulsion was added to 40 parts of water at 50C, and thetemperature of the system raised to C while stirring. This temperaturewas maintained for 30 minutes to polymerize the toluylene diisocyanateand bisphenol A to form the capsule walls. 10 parts of cellulose flockswere added thereto.

The solid contents of the capsule composition thus obtained was 51%. 10parts of a 5% aqueous solution of sodium alginate was added thereto as aviscosity intensifier to provide a viscosity of 5,300 G1.

The capsule solution thus prepared was coated on a base sheet using themetering bar coater shown in FIG. 4. The backing roll was a rubbercoated roll having a diameter of 960 mm with a hardness of 50 Shore, themetering bar was stainless steel and plated with chromium and 6 mm indiameter. As for the applicator roll, a roll of 150 mm diameter platedwith hard chromium was used, and rotated at 20 revolutions per minute.The coating speed was m/min and anexcess amount of capsule compositionwas coated onto the running base sheet. The metering bar was supportedon an elastic stainless steel blade 50 mm long which could be operatedflexibly, and was rotated at 15 revolutions per minute in the directionopposite to the running direction of the base sheet. The applicationpressure of the blade was controlled by adjusting a bolt holding theblade support so as to provide a coating quantity of 5 glm After drying,a pressure-sensitive, color-forming copy sheet was obtained.

Superposing the thus obtained pressure-sensitive, color-forming copysheet on a pressure-sensitive copying clay paper and applying pressurethereto, a clear, black-greenish image was obtained.

A thermal test was carried out as in the Example 1, and it was foundthat the capsules had excellent thermal resistance.

The coated surface is shown in FIG. 6 by photographs taken by a scanningelectron microscope. It was found that the capsules were not broken atall.

EXAMPLE 3 Instead of the 3-diethylamino-7- dibenzylaminofluorane used inExample 2, emerald jasmin Y-l5l4E (a trade name for a perfumemanufactured by Ogawa Koryo KK) was used, and capsules containing theperfume were obtained without adding 10 parts of cellulose flocks.Treating this capsule composition with an atomizing dryer (NitroAtomizer:

Minor Unit Type 53, Danish made), provided a perfume-containing capsulepowder. The obtained capsule powder was redispersed in an aqueoussolution in which starch had been dissolved solution) adjusted its solidcontent to 75% and the viscosity to 34,000 CF.

The capsule composition thus prepared was coated onto a Q-kote film (thetrade name of a polyethylene film manufactured by Nihon Goseishi KK)using a pond-type blade coater as shown in FIG. I. The backing roll wasa rubber coated roll having a diameter of 960 mm with a hardness of 60Shore. The blade was made of steel, with a thickness of 0.25 mm and alength of 15 mm. The blade was operated flexibly and not fixed to thesupporting frame. The blade angle to the backing roll was 42, and thecoating was effected at 90 m/min under a blade pressure of 15 kg/cmAfter drying, a perfume incorporated capsule sheet was obtained.

After leaving this capsule for l or 2 months, there was a fragrant smellof jasmin when the capsule layer was rubbed by hand.

It is thus clear that the capsules are kept sufficiently normal evenwhen they are applied by a blade coater.

EXAMPLE 4 The same treatment as in Example I was effected to except thatthe color forming oil consisting of 50 parts of chlorinated diphenyl and1.0 part of crystal violet lactone was substituted with 40 parts ofAraldite 6020 (the trade name of an epoxy resin having an epoxyequivalent of 210, produced by Ciba Limited) whereby the capsulecomposition was obtained. As in the cited Example, the composition wasadjusted to have a solids content of 25% and a viscosity of 200 CF.

The capsule composition thus obtained was coated onto a base sheet usinga metering coater as shown in FIG. 3. The metering bar was made ofstainless steel plated with hard chromium, and had a diameter of mm. Asfor the applicator roll, a roll 150 mm in diameter and hard chromiumplated was used, and rotated at a speed of 20 rev/min with a coatingspeed of 100 m/min. A surplus amount of capsule composition was coatedonto a running support sheet. The metering bar was rotated in directionopposite to the running sheet at a rate of rev/min, and the lap angle ofthe metering bar to the support sheet was adjusted to 5. The coatingrate was 8 g/m After drying, an adhesive capsule sheet was obtained.

After leaving the capsule sheet for I 2 months, a sheet of paper wasplaced on the capsule surface, and upon pressing the paper by rubbingwith a hand, the two sheets adhered to each other, thus showing asufficient adhesive property. From this, it is evident that the capsulesare normal even when applied with a metering bar coater.

EXAMPLE 5 The capsule composition having a shlids content of 42% and aviscosity of 1500 C.P. obtained in Example 1 was coated onto a basesheet utilizing a metering bar coater as shown in FIG. 4. The backingroll was a rubber covered roll having a diameter of 960 mm and ahardness of 50 Shore. The metering bar was made of stainless steel andplated with chromium. The diamter was 6 mm. The applicator roll had adiameter of 150 mm and was plated with hard chromium. The rotating speedthereof was 18 rev/min. The coating speed was I 10 m/min. A surplus ofcapsule composition was coated on the running base sheet. The meteringbar was supported by an elastic steel blade having a length of 55 mmwhich operated flexibly. The metering bar was rotated in a directionopposite to the running base sheet at a speed of 15 rev/min. Thepressure applied by the metering bar was controlled by adjusting a boltholding the blade supporting frome to provide a coating quantity of 4.5g/m After drying, pressuresensitive, color foiming copysheet wasobtained.

Superposing the thus obtained pressure-sensitive, color-forming copysheet on a pressure-sensitive copying clay paper, a clear, blue imagewas obtained upon copying.

A thermal test was carried out as in the Example 1, and it was foundthat the capsules had excellent thermal resistance.

EXAMPLE 6 In Example 2, 3-diethylamino-7- dibenzylaminofluorane wasreplaced by emerald jasmin Y-l514 (trade name of a perfume produced byOgawa Koryo KK) to provide a capsule composition containing perfume.This capsule composition was treated in an atomizing dryer (NiroAtomizer: Miner Unit Type 53, Danish made), to provide aperfume-incorporated capsule powder. Redispersing the obtained capsulepowder in an aqueous solution to which casein has been dissolved (6%solution) adjusted its solids content to 67% and the viscosity to I1,000 CF.

The capsule composition prepared as above was applied onto a base sheetutilizing a metering bar coater as shown in FIG. 4. The backing roll wasa rubber coated roll having a diameter of 960 mm and a hardness of 50Shore. The metering bar was made of chromium plated steel 8 mm indiameter. As the applicator roll, a hard chromium plated roll having adiameter of 150 mm was used which rotated at 20 rev/min. The coatingspeed was 105 m/min and a surplus amount of capsule composition wascoated onto the running base sheet. The metering bar was 0.7 mm thickand supported on an elastic steel blade having a length of 40 mm whichcould be flexibly moved. The elastic steel blade was rotated in adirection opposite to the running direct ion of the base sheet at aspeed of 15 rev/min.

Leaving the obtained capsule sheet for one or two months, when thecapsule layer was rubbed with a knife there was a fragrant smell ofjasmin.

As a result, it was again made clear that the capsules were in a normalcondition even when they were applied by a metering bar coater.

What is claimed is:

l. A process of producing a capsule-coated sheet characterized by thesteps of applying an excess of a coating composition containingmicrocapsules and having solids content of from about 20 to about 8.0

weight and a viscosity of 50 to 50,000 CI. to a running base sheet andthereafter applying a shearing force by means-of a blade or metering barto the coating composition by directly pressing thereagainst said bladeor bar to remove excess coating composition from said base sheet andspread said composition uniformly over said running base sheet, saidshearing force being insufficient to break said microcapsules.

2. The process of claim 1 wherein said microcapsules have a size lessthan about 1.1.. I

3. The process of claim 1 wherein said microcapsules have a size in therange of from about 10 u to about 50

1. A PROCESS OF PRODUCING A CAPSULE-COTED SHEET CHARACTERIZED BY THESTEPS OF APPLYING AN EXCESS OF A COATING COMPOSITION CONTAININGMICROCAPSULES AND HAVING SOLIDS CONTENT OF FROM ABOUT 20 TO ABOUT 80WEIGHT % AND A VISCOSITY OF 50 TO 50,000 C.P. TO A RUNNING BASE SHEETAND THEREAFTER APPLYING A SHEARING FORCE BY MEANS OF A BLADE OR METERINGBAR TO THE COATING COMPOSITION BY DIRECTLY PRESSING THEREAGAINST SAIDBLADE OR BAR TO REMOVE EXCESS COATING COMPOSITION FROM SAID BASE SHEERAND SPREAD SAID COMPOSITION UNIFORMLY OVER SAID RUNNING BASE SHEET, SAIDSHEARING FORCE BEING INSUFFICIENT TO BREAK SAID MICROCAPSULES.
 2. Theprocess of claim 1 wherein said microcapsules have a size less thanabout 100 Mu .
 3. The process of claim 1 wherein said microcapsules havea size in the range of from about 10 Mu to about 50 Mu .